Rewriting the Bird Family Geneology
Jun 30 at 8:08pm by Aileen
Bird-watching is one of the most popular pastimes in the world, for people from all walks of life. Our fascination with birds in all their sizes, colors and habitats thus makes for a ready field of study in biology, where bird evolution used to maintain a fairly rigorous tree-of-life.
Not so much any longer, since researchers with the Early Bird Assembling the Tree-of-Life Project centered on the Field Museum examined DNA from all major living groups of birds and discovered that phylogenics had it all wrong!
Huge Genome Phylogenic Study of Birds Re-Writes Bird Evolution
As an indicator of just how wrong it was, DNA analysis has determined that falcons - those swift and trainable birds of prey - are NOT closely related to hawks and eagles. Whoa. Spokespersons for the project say the entire understanding of bird evolution will need to be re-written with this new information, and that information itself raises some further questions about concurrent and repeated evolution of certain traits at different times in different families.
“We now have a robust evolutionary tree from which to study the evolution of birds and all their interesting features that have fascinated so many scientists and amateurs for centuries,” Reddy said. “Birds exhibit substantial diversity (largest of the tetrapod groups), and using this ‘family tree’ wwe can begin to understand how this diversity originated as well as how different bird groups are interrelated.”
Evolution’s Practical Joke is Still Funny
May 12 at 6:06pm by Aileen
…after all these years
That great practical joke that life’s designer [be it blind nature or purposeful god] played is still with us to confound orderly notions of biological evolution. The genome of Australia’s duck-billed platypus has been sequenced by an international group of scientists led by researchers at Washington University School of Medicine in St. Louis.
The venomous, egg-laying, duck-billed, web-footed, beaver-tailed mammal is one of the earliest offshoots of the mammalian lineage from when it split off from primitive ancestors some 166 million years ago. The genome confirms the chimeric status of this odd animal which displays traits of reptiles, birds and mammals.
As part of their analysis, researchers compared the platypus genome with human, mouse, dog, opossum and chicken genomes. Chicken genome was chosen because it represents a group of egg-laying animals that includes extinct reptiles that passed on much of their DNA to mammals over the course of evolution. When analyzed, the genetic sequences for venom production in the male platypus was found to have arisen from duplications in a group of genes evolved from ancestral reptilian genomes. They hypothesize that duplications in those very same genes led to the evolution of venom independently in modern reptiles.
The project involved sequencing about 2.2 billion base pairs and 18,500 genes. The Platypus has 52 chromosomes and an unusual 10 sex chromosomes. The platypus X chromosome also bears a striking similarity to the sex chromosome of birds.
Final conclusion? The duck-billed platypus is just as bizarre a mix-and-match critter genetically as it appeared to be when the first specimens were shown to the scientific community some 200 years ago. Skeptics then believed the animal was someone’s idea of a practical joke hoax. Turns out it really is a genetic practical joke, but it comes as-is in nature.
Links:
Platypus Genome Explains Animal’s Peculiar Features
Daily Mail: It’s a bird, it’s a beaver…
World’s Oldest Tree is a Spruce in Sweden
Apr 21 at 9:09pm by Aileen
Most school children have at one time or another encountered a photo of a twisted bristlecone pine tree in California purporting to have begun its life before Abraham left Ur [the ‘Methuselah’ tree at ~4767 years old]. Science Daily reported last week that a spruce tree has been discovered in the Dalarna province of Sweden that is twice that age!
Yes, this not very old-looking little tree has been dated by researchers at Umeå University’s physical geography department at ~9550 years old. Just as interesting is that this ancient tree is a genetically identical clone of a previous tree - from whose roots it sprouted all those many years ago - and which left a few scraps of old wood in the area for researchers to analyze and a laboratory in Miami, Florida to date via C-14.
Researchers combing the Swedish mountains from Lapland to Dalarna have discovered a cluster of about 20 spruces that are all more than 8,000 years old. Which has to qualify the grove as the most ancient stand of virgin timber on the planet.
The Hindu Goddess Baby
Apr 9 at 11:11pm by Aileen
For something different and profound, consider the case of a baby girl named Lali born near New Delhi, India on March 11. She has a rare birth defect called diprosopus that gave her two faces on one head. ABC News reported that the resident medical officer of the Saifi Hospital where Lali was born has thus far been unsuccessful in his attempts to convince the parents to allow CT scans or MRI to determine whether there are duplicated internal organs or invisible, life threatening deformities that might be corrected by surgery.
Most babies with this condition are stillborn or die shortly after birth, but Lali so far has shown no breathing or digestion difficulties, both mouths are being fed. She was born normally and left the hospital with her mother 8 hours after birth.
This condition is not technically a case of cojoined twinning, where a single embryo duplicates and does not completely separate. Rather, it is due to malfunctioning in the developing embryo of a single protein called Sonic hedgehog homolog [SHH]. SHH protein governs the width of the face and features, and governs proper development of the brain and spinal cord via a signaling cascade.
Genes and Not-Genes: Human Genome Shrinks Again
Jan 16 at 5:05pm by Aileen
Human Genome loses nearly 5,000 genes
Back before the human genome had been sequenced biologists estimated that we might have up to 150,000 genes to work with. Genes are those stretches of DNA code sequences between “start” and “stop” codons that are transcribed and used to create functional proteins from amino acids. High initial estimates of how many genes it takes to be a human were the natural result of a “gene-centric” point of view in biology, which assumed that all the particular traits of any organism would be determined by specific genes for those traits. We now know that things are more complicated than that.
When the first draft of the human genome was published in 2001 the approximate number of genes had been pared down - somewhat surprisingly to many - to a mere ~35,000 genes. That number has been whittled down even further over the next few years, and now has been reduced yet again by nearly 5,000. Current estimate: a mere 20,500 genes in the entire human genome.
New Light Shed on Human Evolution
Nov 22 at 2:02pm by Aileen
There have been quite a few recent news reports about research shedding new light on human evolution. Some of it’s in the realm of those interminable Just-So stories biologists never seem to tire of (despite the notable fact that those Just-So stories change regularly according to who’s doing the storytelling today), but some of it’s darned good science.
First up is the newer, better Tale of The Simple Reason Helps Males Evolve More Quickly than females. This one’s particularly entertaining, as Just-So stories go. It comes from researchers at the University of Florida Genetics Institute, to be published in the Proceedings of the NAS. Spokes-researcher Marta Wayne explains it thusly:
“It’s because males are simpler.”
Well Duh. Of course, Wayne explains the long known fact that male inheritance involves simpler genetic architecture as compared to females. No doubt such as the fact that a woman gives birth to the female’s contribution to genetic inheritance of her granddaughters when she gives birth to a daughter. But you’ve just gotta love the conclusion, drawn from research on the ubiquitous fruit fly:
“Researchers believe this relatively uncomplicated genetic pathway helps males respond to the pressures of sexual selection, ultimately enabling them to win females and produce greater numbers of offspring.”
Genetically Engineered Corn Endangers Aquatic Ecosystems
Nov 15 at 7:07pm by Aileen
The Chicago Tribune reports this week that scientists at Loyola University have established that the pollen, leaves and other plant parts of corn engineered to kill the European corn borer with Bt toxins could endanger the American midwest’s aquatic ecosystems when washed into nearby streams.
When eaten by aquatic insects called caddisflies, the Bt toxin stunts growth and increases mortality. These insects are food for fish and amphibians in the ecosystem. The scientists reportedly ‘feel’ that such unanticipated effects of GE technology need to be investigated, but of course the EPA and USDA (and Monsanto) don’t feel that way at all.
It might be difficult to separate the effects of GE plant wastes from the general toxic overload caused by modern agribusiness mega-farming practices, which also cause death and deformity among aquatic life forms and amphibians in midwestern ecosystems. And while consumers at home and abroad have made it known that they do not wish to consume genetically engineered pesticides disguised as food, the new market for corn as ethanol fodder makes it unlikely that GM corn is going to be phased out any time soon.
Related Links:
Older farmers less likely to plant Bt corn
GM corn might affect ecosystems
Eat to Live: 1 million against GM food
Eat to Live: Agriculture inspectors chided
Another Example of Irresponsible Science News?
Oct 24 at 6:06pm by Aileen
Continuing the theme of bad science writing - confusing or completely ridiculous headlines, absurd assertions of fact and fancy, questionable conclusions, etc. - take a look at the screenshot below of the BBC website’s lead story in their ‘Health’ section this past Monday…
Now, it might give you a chuckle, as it did me. But come on, folks… I hereby add ‘Irresponsible Use of Illustration’ in science news reporting as yet another category for the Science News Booby Prizes at year’s end. After last week’s sordid destruction of Nobel Laureate James Watson’s storied career as a notorious bigot, this sort of thing can definitely make one wonder what the heck these science reporters are thinking.
If they are in fact thinking at all.
Beware The Bong: Paraphernalia Addiction
Oct 18 at 6:06pm by Aileen
Plus… DNA Pioneer Watson Steps in it Again
This week there are a couple of notably humorous science news stories making the rounds, to the delight of all science-watchers who sometimes suspect that scientists take themselves way, way too seriously.
First up we have researchers at the University of Memphis informing us that Water pipe use is as addictive as smoking.
Whoa! Who’d have thought that the pipe you smoke is as addictive as what you’re smoking through it? Yet this is just what Dr. Wasim Maziak warns…
“As water pipe use is increasing throughout Europe and North America it is very important that we initiate comprehensive research efforts to combat this looming epidemic,” Maziak said in a statement.
Don’t laugh too hard. Someone funded this research, and it was probably us.
Cosmic Billiards, Extinction, Love, Sex and Depression
Sep 14 at 6:06pm by Aileen
…plus a Blog Slam just for fun!
This week there’s lots of news from the fields of biology, medicine and psychology about people. What they want, what they do, and what makes them that way. But I’ll start with the famous extinction event that wiped out the dinosaurs ~65 million years ago, making room for humans to evolve at all.
U.S. and Czech astrophysicists reported that a Large Asteroid Breakup May Have Caused Mass Extinction at that time. They created a clever simulation of the disintegration of a giant asteroid in the belt roughly 100 million years ago, which caused an asteroid bombardment of the earth and moon as fragments crossed our path.
Yet more evidence to add to the iridium layer that tells us what most likely happened to those gentle and not-so gentle reptilian giants who once dominated the planet.
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